The semiconductor industry has experienced rapid growth due to continuous improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more components to be integrated into a given area. As the demand for even smaller electronic devices has grown recently, there has grown a need for smaller and more creative packaging techniques of semiconductor dies.
As semiconductor technologies evolve, three dimensional integrated circuits have emerged as an effective alternative to further reduce the physical size of a semiconductor chip. In a three dimensional integrated circuit, active circuits such as logic, memory, processor circuits and the like are fabricated on different wafers and each wafer die is stacked on top of a packaging component using pick-and-place techniques. Much higher density can be achieved by employing three dimensional integrated circuits. In sum, three dimensional integrated circuits can achieve smaller form factors, cost-effectiveness, increased performance and lower power consumption.
A three dimensional integrated circuit may comprise an integrated circuit die, an interposer and a package substrate. More particularly, the integrated circuit die is attached to a first side of the interposer through a plurality of solder bumps. Solder bumps are used to provide electrical connection between the integrated circuit die and the interposer. A second side of the interposer is attached to the package substrate by a plurality of interconnect bumps. Interconnect bumps such as solder balls may provide electrical connection between the interposer and the package substrate, which in turn makes electrical connection to a printed circuit board through a plurality of package leads.
In order to reduce the potential solder failure between the integrated circuit die and the package substrate caused by thermal stresses, the interposer is employed to provide a matching coefficient of thermal expansion to the integrated circuit die. The interposer also provides adaptation between smaller contact pads with reduced pitch on an integrated circuit die and larger contact pads with increased pitch on a package substrate. In addition, the interposer may further comprise a variety of circuit elements. These circuit elements may be active, passive, or a combination of active and passive elements.
Three dimensional integrated circuits have some advantages. One advantageous feature of packaging multiple semiconductor dies vertically is that three dimensional package techniques may reduce fabrication costs. Another advantageous feature of three dimensional semiconductor devices is that parasitic losses are reduced by employing various interconnect bumps.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale.